Propeller for helicopterous aircraft



Aug. 11, 1931. J. MELLANDER I PROPELLER FOR HELICOPTEROUS AIRCRAFT FiledNov.

Jnuemlgr Patented Aug. 11, 1931 NITED STATES PATENT OFFICE I JEANMELLANDER, F BRUSSELS, BELGIUM PROPELLER FOR HELIClOPTEROUS AIRCRAFTApplication filed November 23, 1925, Serial No. 70,983, and in BelgiumNovember 28, 1924.

The invention relates to propellers for heli copters and specially tothose in which the propeller is situated above the body and constitutes:(1) a new Way of obtaining such an air pressure under the propellerblades that simultantously with the ascensional power a propelling forceshall be induced. (2) The new method to use this propelling force toretain the propeller shaft upright,

or to redress it, when tilted. (3) To obtain by this new method a stateof stable equilibrium.

The drawings show graphically in Fig. 1 a horizontal propeller with theblades inclined; Fig. 2 an inclined propeller; Fig. 3 a propeller with amovement for inclining the blades radially; Fig. 4 a propeller with amovement for obtaining a stable equilibrium and 'Fig. 5 shows a realizedpropeller.

Thenew way of obtaining the propelling force consists 'in the fact, thatthe blades, without any; tilting of the propeller shaft, can be inclinedin the 'radial sense to the horizontal, exactly as if the propellershaft I had been tilted. See drawings, Figuresl and 2.

This radial inclining of the blades is obtained in the following"manner, that each blade oscillates on ageometrical transversal 80 axis,this ideal axis passing horizontally through the air pressure centreunder the blade, and that, during each revolution of the propeller, theblades can be forced, by suitable means, to vary this radial inclina- 85tion between zero and a maximum desired.

There will be several ways of inclining. the blades e. g. a methodresembling those already used by different helicopters, for varying theincidence angle. Fig. 3 of the draw- 19 ings shows graphically a newmethod, consisting in this, that every blade 2, oscillating on atransversal axis 3, at a certain distance from the propeller axis 1, ina point 4,-at a certain distance from the oscillating axis 3,

is connected by means of an articulated link l 5, with one arm 6 of theknee lever 7, having its centre of oscillation 8 most favorablycoinciding with the common centre of rotation of the air pressurecentres under the blades and having the end of its other arm Versaljoint.

9, rotating on a bearing 10, supported by, and its position controlled'by a lever 11, having its oscillatirig centre 12, on the body of theaircraft itself, thus enabling, by mean of the lever 11, the arm 9 ofthe kneelever, to rotate round a geometrical axis, at a certaininclination to the propeller axis, thus forcing opposite blades toincline radially in the same sense, and, during everyrevolution of thepropeller, to vary their radial inclination between .zero and a maximumdesired, imparting simultaneously to the blades an ascensional power 13and a propelling force 14:. I

Fig. 4 of the drawings shows a scheme, giving to the propeller a stateof stable equilibrium around its tilting centre 12, thus obtained atfirst by a weight 14, attached to an arm 13, connected with the lever11', having its oscillating centre most favorably coinciding with thetilting centre of the propeller shaft, at a certain distance under thecentre of oscillation 12, thus forcing lever 11, in spite of themovements of the aircraft, by gravitation only, to retain approximatelythe same position to the horizontal, and secondly by giving the levers6, 9 and 11, such I lengths, that the blades incline quicker than thepropeller axis, to the horizontal, when the propeller axis, by thegliding of the propeller head, due to exterior forces, inclines to oneor other-direction, thus increasing the propelling force 14, inproportion to the gliding of the propeller head, until it neutralizesthe exterior forcesand brings baclg the pro peller head to its normalposition, above the body of the aircraft, as soon as the exterior forceshave ceased to operate.

Figure 5 of the drawings shows one of the ways of constructing such apropeller. The propeller shaft 1 can be rotated in any known manner,either directly in bearings, or by means of a universal joint, and totilt around a geometrical point 21, this, in the first case, being mostfavorably coinciding with the centre of resistance of the aircraft body,and in the second case with the centre of the uni- The hollow shaft 1carries the ring 4, by means of the wires 2 and 3, and this ring carriesthe blades 6, by means of the little arms 5, and the pivots in thepoints 7 The knee lever is composed of the'arm 8, oscillating at theball pivot 9, fixed to the a shaft, supplied with the little arms 11,passing through suitable holes in the shaft, carrying the circularelement 12 and this the ring 18, by means of the wires 14 and 15. Thisring is connected with the blades at the points 17, by means of thearticulated links 16. The end 10 of the arm 8 rotates on the bearing 18,carried by lever 20, by means of the articulation 19, having itsoscillating centre 21 coinciding with the tilting centre of thepropeller shaft, on an arm 22,1ixed on the 15 aircraft body and stickingup in the hollow shaft. Lever is supplied with the arm 23, and thiscarries a weight 24:. The levers 20 and 8 and the radius of the ring 13,are of such lengths, that the blades incline quick- 20 er than thepropeller axis to the horizontal.

Figure 6 of the drawings shows another method of construction having asolid shaft 1, whilst the circular element 12 is directly oscillating onthe ball 9, fixed to the shaft.

25 Thiscircular element is supplied with two or more arms 10, rotatingtogether on the ball-bearing 18, and this, by means of the articulatedlink 19, is connected with the lever 20, having its oscillating centre21 on an arm 22, fixed to the aircraft body.

I claim as new:

1. Propellers for helicopters comprising a shaft, a mounting on saidshaft comprising radial arms for carrying the blades, blades mountedmovable to oscillate on axes transverse to said arms and means forcontrolling the radial inclination of the blades,

2. Propellers for helicopters comprising a shaft, a mounting on saidshaft comprising radial arms for carryingthe blades, blades mountedmovable to oscillate on axes trans verse to said arms, the knee leverconnected with the blades and means for controlling the position of thislever and thus the radial in-' clination of the blades.

8. Propellers for helicopters comprising a shaft, a mounting on saidshaft comprising radial arms for carrying the blades, blades mountedmovable to oscillate on axes transverse to said arms, the knee leverconnected with the blades and with another lever, having its positioncontrolled by a weight.

JEAN MELLANDER.

